1. Field of the Invention
The present invention relates to a wireless transmitting and receiving apparatus performing a bluetooth method, and more particularly, to a time division duplex (TDD) type power amplification module functioning as an amplification line in a transmission mode and as a transmission line in a receiving mode.
2. Description of the Related Art
A bluetooth method is an industrial standard of the computer and telecommunication industries for transmitting and receiving data in a high speed using a wireless frequency without using a physical communication cable between electronic apparatuses. The bluetooth method is used for a short-distance wireless connection among mobile phones, computers, and PDAs. Using the bluetooth method, the data having a predetermined frequency width is transmitted between the apparatuses spaced-apart from each other by tens meters in a speed of 764 kbps using a transmission power of 1 mW by frequency-hopping among 79 independent 1 MHz channels having a center frequency of 2.402 to 2.478 GHz. The bluetooth method is to comply with a time division duplex (TDD) method of alternatively transmitting and receiving the data.
In addition, an apparatus performing the bluetooth method provides maximum 3 channels of audio channels as well as a data channel, and enables a point-to-point or multi-points connection.
Using this technology, it is possible that a cellular phone, wireless pager, or PDA user can buy a single phone having three functions of a cellular phone, a wireless pager, and a PDA. The single phone functions as a home and office mobile phone to be able to be synchronized with information stored in desk-top or notebook computers, transmits and receives a facsimile letter, and prints the data.
Generally, the single phone incorporates mobile and non-mobile computer apparatuses. Each apparatus needs to be mounted with a bluetooth transceiver chip (IC) to perform the bluetooth method.
According to definitions of the industrial standard of the bluetooth method, the bluetooth apparatus is classified into class I, class II, and class III based on a transmission output power.
The apparatus having the class II generally has the transmission output power of 0 dBm (a transmitting and receiving distance of about 10 m). As shown in FIG. 1, the apparatus having the class II includes a bluetooth module 10 performing the class II. The class II bluetooth module 10 includes a bluetooth transceiver IC 11 modulating or demodulating transmitting or receiving data (signal) using the TDD method according to the bluetooth method, first and second matching networks 12, 13 coupled to a transmitting signal terminal TX and a receiving signal terminal RX of the bluetooth transceiver IC 11, respectively, to perform an impedance matching, a TDD transmitting and receiving switch 14 alternatively selecting one of the first and second matching networks 12, 13 according to a TDD transmitting-on (TDD-TXON) control signal outputted from the bluetooth transceiver IC 11, and a frontend filter 15 coupled between the TDD transmitting and receiving switch 14 and an antenna ANT to filter the transmitting and receiving data.
The class II bluetooth module 10 has a transmission distance of 10 m by transmitting the transmitting signal without amplifying the transmitting signal to be transmitted.
To the contrary, a class I bluetooth module 20 as shown in FIG. 2 has the transmission distance of 100 m using the transmission output power of 20 dBm of the transmitting signal.
Referring to FIG. 2, the class I bluetooth module 20 includes a bluetooth transceiver IC 21 modulating and demodulating the transmitting signal and the receiving signal according to the bluetooth method, first and second matching networks 22, 23 coupled to a transmitting signal terminal TX and a receiving signal terminal RX of the bluetooth transceiver IC 21 to perform impedance-matching, a power amplifier 24 coupled to the first matching network 22 to amplify the transmitting signal according to a control signal of the bluetooth transceiver IC 21 in a transmitting mode, a third matching network 25 coupled to an output terminal of the power amplifier 24 to perform the impedance-matching, a transmitting and receiving switch 26 alternatively selecting one of the second matching network 23 and the third matching network 25 according to a TDD transmitting-mode-on signal outputted from the bluetooth transceiver 21, a frontend filter 27 coupled between the transmitting and receiving switch 26 and an antenna ANT to filter the transmitting signal and the receiving signal.
The class I bluetooth module and the class II bluetooth module are alternatively selected according to the transmission distance of the bluetooth apparatus.
Generally, since a manufacturer of the bluetooth module develops and supplies the class I bluetooth module and the class II bluetooth module separately, the manufacturer of the class II bluetooth module needs an additional development period and manpower to develop the class I bluetooth module. Accordingly, a manufacturing cost of the class I bluetooth module is increased, it costs a lot for a user to use the class I bluetooth module which is less demanded than the class II bluetooth module. With this reason, the supply of the class I bluetooth module is less than the class II bluetooth module.
Recently, a class II bluetooth module 30 includes a highly integrated bluetooth transceiver, such as a bluetooth transceiver 31 integrated with matching networks 311, 312 and a TDD transmitting and receiving switch 313, as shown in FIG. 3. The class II bluetooth module 30 may further include a balun transformer 32 converting a balanced signal to an unbalanced signal as well as a frontend filter 33. The highly integrated bluetooth transceiver may be integrated with the balun transformer 32 and the frontend filter 33 which have not been integrated with the highly integrated bluetooth transceiver.
However, if the highly integrated bluetooth transceiver is integrated with the TDD transmitting and receiving switch 313 to be used in the class II bluetooth module as shown in FIG. 3, it is very difficult to connect the power amplifier, which is not integrated in the highly integrated bluetooth transceiver, to the highly integrated bluetooth transceiver due to heat and electro-magnetic wave generations occurring during manufacturing the class II bluetooth module.